In the development of logistics systems there is a trend towards an ever greater degree of automation in order to save costs and time and increase the profitability of the systems. Storage into, and retrieval from, a high-rise installation is therefore frequently effected by automated, computer-controlled rack-mounted storage/retrieval machines. In the output area of a storage system the articles required for an order are loaded onto a means of transport, such as a lorry. For many applications, such as e.g. in the retail trade, a delivery order comprises a plurality of different articles which are loaded by means of load carriers, such as e.g. pallets provided with rollers, onto lorries which deliver them to the individual branches.
Loading the load carriers and/or pallets with the articles, which generally take the form of packing units or collis (e.g. cardboard boxes or shrink-wrapped product packs), has hitherto been done mostly by hand. Building up such a load stack on a pallet requires a lot of skill in order on the one hand to form a stable loading stack, which for transportation is wrapped e.g. in stabilizing film, and on the other hand to achieve optimum utilization of space and as high a loading stack as possible for transportation in the lorry. Manual pallet loading is therefore time-consuming, requires skilled and experienced workers and is a factor limiting the profitability of the logistics system. The manual loading of load carriers with occasionally heavy packing units under ergonomically unfavourable conditions is moreover bad for the health of the workers engaged in loading.
It is therefore known to load pallets by means of a gripper system. In said case, the packing units (collis) to be handled, such as cardboard boxes and the like, are gripped laterally by gripping arms of the robot or from above by vacuum suckers and then loaded according to predetermined rules onto the pallet. The drawback of this is, however, that vacuum grippers are usable only with smooth and stable materials and lateral gripping arms may easily slide off or cause damage to delicate packaging. What is more, the use of laterally applied gripping arms inevitably leaves gaps between the packing units in the loading stack on the load carrier, thereby preventing optimum utilization of space and stability owing to the gaps left between the packing units.